//
// Copyright (c) 2018 Advanced Micro Devices, Inc. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
#pragma once

#include <iostream>
#include <atomic>
#include <mutex>
#include <thread>

namespace vez
{
    class SpinLock
    {
    public:
        void Lock()
        {
            auto callingThread = std::this_thread::get_id();
            if (callingThread == m_owningThread)
                return;

            while (true)
            {
                bool value = m_lock.test_and_set(std::memory_order_acquire);
                if (!value)
                {
                    m_owningThread = std::this_thread::get_id();
                    break;
                }
            }
        }

        void Unlock()
        {
            m_lock.clear(std::memory_order_release);
            m_owningThread = std::thread::id();
        }

    private:
        alignas(64) std::atomic_flag m_lock = ATOMIC_FLAG_INIT;;
        std::thread::id m_owningThread = std::thread::id();
    };
}

#define BEGIN_THREAD_SAFE_BLOCK() {\
static vez::SpinLock spinLock;\
spinLock.Lock();

#define END_THREAD_SAFE_BLOCK() \
spinLock.Unlock(); }
